The aim of this project is to develop and optimize our novel particle-based microarray platform, ArrayableESP, for application to high multiplex (50- to 2000-plex) proteomic analysis of human serum samples. ESPs are optically-encoded microfabricated particles that can be manipulated using magnetic force. They are manufactured on commercially available photolithographic equipment using efficient and robust techniques borrowed from the semi-conductor industry. They have significant advantages in cost throughput, scalability, and flexibility over existing bead-based liquid array platforms. We will use aptamers, instead of antibodies, on our platform, which will eliminate the need for sample pre-labeling/pre-processing and allow for a parallel method of homogeneous detection following protein binding. The combination of the ArrayableESP platform with aptamers is expected to increase accuracy of analysis and result in a simplified workflow. Such attributes, in combination with the nearly unlimited multiplex potential offered by the ArrayableESP platform, will provide a multiplex product with significant advantages over currently available technologies for proteomic analysis. ESP technology has broad applicability and should be a valuable tool in the diagnosis, prognosis, and characterization of a variety of disease states, including cancer, heart disease, arthritis and inflammatory diseases, kidney disease, liver disease, allergic responses, and infectious diseases (e.g. HIV).